AbstractShock wave propagation and spallation within materials submitted to laser shock have been investigated for roughly two decades. The characteristic durations studied were mainly in the nanosecond range. However, with the latest laser technologies evolution, one can access shorter regimes in durations, going below the picosecond. In the continuity of the studies performed in nanosecond regime, experiments have shown the possibility to obtain reproducible spallation at the micrometric range (spall thicknesses below 10 μm). The spalls observed show a planar rupture surface. The results obtained by post-mortem observation show that the spall thickness is thinner if the target thickness is reduced. The study is orientated to the two-dimensional damage which is caused by edge effects. This phenomenon is due to the limited loaded surface and the laser space repartition. These effects are particularly visible through the spall diameter. Shots on aluminum targets of various thicknesses with different laser spot diameters show the thicker the target, the smaller the diameter. This reduction is caused by the edge effects development which alters the tension state space repartition responsible of spallation. These data combined with a two-dimensional simulation can inform about the material dynamic damage behaviour.